Reactions of vanadium(II) with the µ-amido[aquotetra-amminecobalt(III)], [chlorotetra-amminecobalt(III)], and chloropenta-amminecobalt(III) complexes. A comparison of kinetic data

Abstract

The reaction of the µ-amido[aquotetra-amminecobalt(III)][chlorotetra-amminecobalt(III)] complex with vanadium(II)(i) is first-order in each reactant and independent of [H⁺] over the range 0·2–1·9M. At 25° and V²⁺+(NH₃)₄Co[graphic omitted]Co(NH₃)₄⁴⁺ [graphic omitted] V³⁺+ Co(NH₃)₅H₂O³⁺+ Co²⁺+ 4NH₄⁺(i)µ= 2·0M(LiClO₄)K₁= 9·4 l. mole^–1 sec.^–1, ΔH₁‡= 7·8 ± 0·1 kcal. mole^–1, and ΔS₁‡=–27·8 ± 0·3 e.u. The intermediate aquopenta-amminecobalt(III) reacts subsequently with vanadium(II) with K₂= 0·94 l. mole^–1 sec.^–1 at 25°. Kinetic data obtained for the reaction of chloropenta-amminecobalt(III) with vanadium(II) are almost identical to those of the binuclear complex. At 25° with µ= 2·0M(LiClO₄)k₃= 10·2 l. mole^–1 sec.^–1, ΔH₃‡= 7·5 ± 0·15 kcal. mole^–1, and ΔS₃‡=–28·8 ± 0·5 e.u.